The United Nations aid chief called the two major earthquakes that devastated Türkiye's southeast and Syria's northwest the "worst event" to hit the region in a century.

"What happened here on Monday, the epicenter of the earthquake, was the worst event in 100 years in this region," Martin Griffiths, the U.N. under-secretary-general for humanitarian affairs and emergency relief coordinator, told a news briefing in Kahramanmaraş, the epicenter of the quakes.

Noting that more than 100 countries have sent first responders to help Türkiye, Griffiths explained: "We're going to need more than that ... I am here to make sure that these people (quake victims) also are not forgotten."

The U.N. official added that the U.N. and all the nations it represents stand in solidarity at the time of this great tragedy.

Pointing to the importance of the first 24 hours after the quake, he praised Türkiye's response to the catastrophe as "extraordinary."

"We have a clear plan tomorrow, the next day, to give an appeal for a three-month operation to help the people of Türkiye with humanitarian assistance, and we will do some similar for the people of Syria," he also said.

Meanwhile, Griffths also said a recovery phase is approaching in Türkiye's 10 earthquake-devastated provinces, which will rely on humanitarian assistance.

"We're coming to the end of the rescue phase. And after the rescue phase comes to the recovery phase. Typically that relies on humanitarian assistance. It relies on the beginning of planning for rebuilding houses and apartments and buildings," he said.

"And so that's the phase where my community, the humanitarian community, comes into play, and that's why we're going to do an appeal tomorrow or the next day to raise money to provide funding for agencies to come and help the people who've been affected," he added.

On the housing situation, he said the Turkish government will be in the lead in rebuilding destroyed houses, while the U.N. will be directing humanitarian assistance "for the emergency phase, for the period when they may have to live in temporary accommodation."

He stressed that the second phase after the natural disasters could be more concerning in Türkiye and in affected Syria as victims will need help with their livelihoods, food, and medicine.

"We're apprehensive, as you know, about the second phase of a natural disaster of this size is often a medical one, where we have huge worries here and in Syria, of the health problems which have been going on treated," he said. "So agencies, the World Health Organization, and others come in to help give the people what they deserve."

Coming aid to be used 'rightly' in Türkiye

As several countries have already sent field hospitals to Türkiye, Griffiths said he is sure that the Turkish government will coordinate which aid should be placed and where, so the assistance can be successful.

"I'm sure that the aid that comes into Türkiye will be used in the right way and sent to the right places, but it's going to be a huge operation. We're just seeing the beginning of it," he said.

He added that the U.N. Humanitarian Office has agencies that can set up mobile clinics, which he called "incredibly important" at this stage.

Appeal for Syria to be launched within days

Stating that he would be able to see the situation in Syria himself in the following days, Griffiths said, "it's reasonable to assume" that in northwest Syria, where people had already been suffering from the effects of the civil war since 2011, they must be suffering even more today.

"It's also going to be very important to get aid to those people," he said, adding that the U.N. also works in Syria, delivering assistance thereby convoys coming daily from the Bab al-Hawa border gate in Cilvegozu, Türkiye towards Idlib, Syria.

He underlined that U.N. exists as a channel for every government to send aid to Syria.

"That's why we will also be launching an appeal for Syria in the next couple of days for three months," he stated.

Over 21,800 people were killed and over 80,000 others injured by two strong earthquakes that jolted southern Türkiye on Monday, according to the latest official figures. However, hope remains as more survivors emerge from quake rubble on day six of rescue efforts.

In neighboring Syria, the death toll has climbed above 3,300, with more than 5,200 people wounded, according to compiled figures.

The magnitude 7.7 and 7.6 quakes on Monday affected more than 13 million people across 10 provinces, also including Adana, Adıyaman, Diyarbakır, Gaziantep, Hatay, Kilis, Malatya, Osmaniye, and Şanlıurfa.

Several countries in the region, including Syria and Lebanon, felt the strong tremors that struck Türkiye in less than 10 hours.